Mailing the story:

Collecting debugging information from the Linux™ kernel using printk is a well-known method -- and with Kprobes, it can be done without the need to constantly reboot and rebuild the kernel. Kprobes, in combination with 2.6 kernels, provides a lightweight, non-disruptive, and powerful mechanism to insert printk's dynamically. Logging debug info such as the kernel stack trace, kernel data structures, and registers has never been so easy!